Variable delivery gear pump



C. A. MOORE ET AL Aug. 25, 1936.

VARIABLE DELIVERY GEAR PUMP Filed Sept. 14, 1934 3 Sheets-Sheet 1 b mmww O 0 c E LI m w w w m mA IM A Aug. 25, 1936. c. A. MOORE El AL 2,052,419

VARIABLE DELIVERY GEAR PUMP Filed Sept. 14, 1934 3 Sheets-Sheet; 2

. INVENTOR. Cha r'lzs A Mao r e Prs fen Whifcomb ATTORNEYS Aug. 25, 1936. A, RE E AL 2,052,419

VARIABLE DELIVERY GEAR PUMP Filed Sept. 14, 9 4 3 Sheets-Sheet 5 INVENTOR. Cha rlzs A -M 0ore Pr'esfon whlfcom b ATTORNEYS Patented Aug. 25, 1936 UNITED STATES PATENT IOFFICE VARIABLE name! can rent? Charles A. Moore, Greenwich, Conn., and Preston Whltcomb, Kenmore, N. Y.. minors to Manning, Maxwell a Moore, Inc., New York, N. Y., a corporation of New Jersey I Application September 14,1934, Serial No. 743,932 e Claims. (01. 103-120) This invention relates to improvements in gear pumps by means of which the delivery the; of may be varied.

An important object of this invention is the provision of an improved form of gear pump by means of which the amount of fluid displaced for any given speed of operation may be varied.

The common practice with gear pumps at present in order to accomplish variable flow involve the use of a bypass by means of which some of the fluid is shunted ofi from the main stream. When the'pumps of this type are employed with rotary engines and similarequipment, by-passing a portion of .the constant volume output of the pump results inthe exertion of a constant torque by the power device; A constant horse-power output is by much the more desirable characteristic of such equipment but has been incapable of attainment because of the lack of a correct way to vary the output of the pump. With the present invention involving a variable delivery o f the volume of fluid from the discharge output of the pump the engine connected thereto may have a constant horse-power output.

Many other objects are successfully secured by means of this invention.

- This invention resides substantially in the combination, construction, arrangement and relative location of parts in accordance with the following description.

In the drawings,

Fig. 1 is a central, longitudinal, cross sectional view through a form of pump in accordance with this invention employing spur gears which may have either straight or spiral teeth;

Fig. 2 is a cross sectional view on the line 2--2 of Fig. l; Fig. 3 is a cross sectional view on the line 2-4 of Fig. 1; V

Fig. 4 is a cross sectional view on the line 4-4 of F18. 1; I

Fig. 5 is a central, longitudinal, cross section view through a modified form of pump struc- Of course, the pump may be operated at variable speeds but this involves expensive control equipment and a variable power source for operating the pump, which requires complicated and expensive operating and control mechanism. Thus, 5 with present practice, gear pumps have a constant displacement and the quantity of fluid flowing therefrom is varied by by-passing the neces-* sary portion thereof.

With the presentinvention geared pumps are constructed so as to have a variable displacement. The structure is so arranged that the meshing gears may be moved axially with respect to each other to vary the area of the meshing portions of the gears. The result is that at a constant speed of operation the displacement of the pump may be varied at will. The advantages of such an arrangement are manifold. In the case, however, where such pump is used in combination with a rotary engine a constant horsepower output may be secured, imparting to the combination practical capabilities not heretofore attained.

The form' of pump in accordance with this invention, illustrated in Figures 1-4, inclusive, emplays externally meshing gears which may have either straight or curved teeth. The structure comprises a casing composed of the tubular portion I 2, the cap portion 33, and the end plate i3, all secured together to form a closed chamber. The end plate I! is provided with an internally projecting hub portion M which has a longitudinal bore therethrough. The operating shaft I5 is journalled inthis bore in the bearing member l6 and passes through a packing gland nut i8 5 and packing ll. Intermediate the ends of the shaft I! it is enlarged and provided with gear teeth 20 on the periphery thereof.- The exten-v sion IQ of this shaft is iournalled in the cap piece 28. A longitudinally slidable member 2! is formed 40 with a reduced extension 22 which has secured on the end thereof a collar 23 forming a unit having an annular extended peripheral groove. Surrounding the core of this groove are a pair of bearing members 2! upon which is rotatably supmember secured to the end plate It. The member 2| has a longitudinal surface recess 2| of circular cross section snugly fitting the surface of the hub l4 and the gear 20 (Fig. 2). The casing is provided with a pair of diametrically opposed threaded passages ti and 32 which extend to and from the meshing gears Ill and 25. The member 21 is provided with a passage 85 so that any trapped fluid between this member and the end plate may escape to the other side of the upon the area of the teeth 20 and 25 in contact.

By rotating shaft 25, which may be accomplished by means of a crank on its end 21, for example, the member 2| may be moved back and forth, carrying with it the gear 25. When the member moves to the left from the position shown in the figure the meshing area of the teeth increases while movement in the opposite direction decreases the meshing area, with the result that the displacement of the pump is increased or decreased, respectively. It is clear from the description of the structure that rotation of shaft 26 can only effect. movement of member 2| and its attached parts since this shaft is locked against endwise movement. It isequally clear to those skilled in the art thatthis pump may be employed as a motor, in which case fluid under pressure is delivered to the gears to cause them to revolve, with the result that power may be taken from shaft i5.

The principles of this invention are illustrated as applied to an internal gear pump, as has been depicted in Figures 5-8, inclusive. In this form the casing comprises the central portion 40, the end cap 4|, the extension portion 42, and the end plate 43, all of which are secured together to form a closed chamber. At 44 is the operating shaft for the pump which extends through a packing 45 and a packing gland nut 48 in the end cap 4|. This shaft has a collar 41 intermediate its ends which abuts against one wall of the portion 40 of the casing and is provided with a collar 43 pinned thereto which-abuts against the opposite face of this wall. Thus the shaft 44 is held against longitudinal movement. The end 49 of this shaft is splined, as shown, and engages with a splined bore II in the spur gear or pinion 50. The right hand end of this gear is provided with a reduced hub which is journalied in a bearing member 52 held in place by means of a collar 53 secured to the hub. The other end of the gear is provided with a shaft extension 54 likewise provided witha collar 55 secured to its free end. This shaft 54 is mounted in a bearing member 56. The gear 50, bearing member 52, collar 53, shaft 54, collar 55 and bearing member 56 are thus all securely locked together for unitary movement. A crescent-shaped fixed filler piece 51 is secured in the portion 42 of the housing by means of pins so as to engage the upper portion of the bearing member 51 which has been shaped to provide a running fit therewith. At 58 is an internal or ring gear journalled in the housing between the portions 40 and 42 of the casing. At 80 is a small shaft or rod which exand rests against, at its free end, a thrust bearingtends through a threaded extension '8 on the end cap 43 andexternally of a sleeve 84 mounted on this extension. A packing 68 and a packing gland nut 81 prevent leakage around this shaft.

The shaft is provided with a collar Ii which en- 5 gages the end plate 43 in a recess and has secured thereto a collar 65 which engages the outer face of the extension 63. This construction prevents longitudinal movement of shaft 50 when it is revolved. The end 62 of this shaft threadedly engages the bearing member 58. Thus when shaft 80 is revolved the assembly including the spur gear 50 may be moved axially. This engagement with the operating shaft 4 is maintained through the splined connection. The bearing member 52 l is provided with a lug or key I! which slides in a groove 13 in the part 40 of the housing. Thus the bearing member 52 may slide back and forth with gear 50 but may not turn. The inlet and outlet passages" and ll extend partway into 20 the bearing member 52 and issue at'oneside (see Figure'S) so that the fluid is passed from one to the other by the gears. In view of the description previously given, the operation of this pump to effect variable displacement at constant speed will be apparent. Here, as before, the pump may be reversed in its action and employed as a motor.

From the above description it will be apparent that this invention resides in certain principles of construction and operation as illustrated in the drawings. It is recognized that those skilled in the art may readily vary the application of these principles and the structure by which they are applied without departure from the scope of this invention. We do not, therefore, desire to be strictly limited to the disclosure as given for purposes of illustration, but rather to the scope of the appended claims.

What we seek to secure by United States Letters Patent is:

1. A variable delivery gear pump of the type described comprising a casing forming a closed chamber, a ring gear 'journaled for rotation in the casing, a pair of spaced bearing members slidably mounted in the casing, a pinion closely fitting 45 between and journaled in said members meshing with said ring gear, a driving shaft journaled in said casing and having a splined connection with said pinion for effecting rotation thereof, and means mounted in said casing and engaging one so of said bearing members for effecting longitudinal reciprocation of the bearing members and pinion to vary the discharge of the pump, said casing having inlet and exhaust ports.

2. In a variable delivery gear pump of the type 55 described the combination comprising a casing forming a closed chamber and having an inlet and an outlet port, a ring gear mounted in said casing for rotation, a pinion meshing with said ring gear,. a pair of bearing members in which said pinion is journaled, said bearing members being slidably mounted in the casing, means for securing said bearing members to said pinion for sliding movement therewith, a,driving shaft journaled in said casing and having a splined connec- 65 tion with said pinion, means for preventing rotation of one of said bearing members, and means engaging the other of said bearing members for effecting longitudinal movement of both searing members and pinion, said last means preventing rotation of the adjacent bearing member.

3. A variable delivery gear pump of the type described comprising a closed casing having an inlet and an outlet port, a ring gear mounted in said casing for rotation on a fixed axis, a pinion meshing with said ring gear, a pair of bearing members in which the pinion is Journaied at opposite ends to rotatably support the pinion on an axis eccentric with the axis of the ring gear, said bearing members being secured to said pinion for longitudinal reciprocation therewith, a driving shaft journaled in said casing and having a sliding connection with the pinion, and means threadedly engaging one of said bearing members for effecting longitudinal reciprocation thereof conjointly withthe pinion.

4. A variable delivery gear pump of the type described comprising a closed casing having aninlet and an outlet port, a ring gear mounted in said casing for rotation on a fixed axis. a pinion meshing with said ring gear, a pairof bearing members in which the pinion is journaied at oppositeends to rotatably support the pinion on an axis concentric with the axis of the ring gear, said bearing members being secured to said pinion for longitudinal reciprocation therewith, a driving shaft journaled in said casing and having a sliding connection with the pinion, means threadedly engaging one of said bearing members for effecting longitudinal reciprocation thereof conjointly with'the pinion, and a fixed filler plate for filling the space between the ring gear and the pinion, one of said bearing members cooperating with the ring gear and the tiller plate as the pinion varies in its area of meshing with the ring gear to block the space between the ring gear and filler plate.

5. A variable delivery gear pump of the type described comprising a closed casing having an inlet and an outlet port, an internal gear journaled for rotation in said casing, a carrier slidably mounted in the casing, a pinion journaled on said carrier and meshing with said gear, a shaft having aligned relatively slidable parts journaled in said casing and connected thereto for driving said gear and pinion, and means threadedly engaging the carrier for effecting longitudinal reciprocation thereof to vary the meshing area of the gear and pinion, one of the shaft parts being held against axial movement and the other connected to said carrier for sliding movement therewith.

6. A variable delivery gear pump comprising a casing having an inlet and an outlet port, and

internal gear rotatably mounted in the casing, a pair of spaced bearing members slidably mounted in the casing, a shalt having two relatively slid- 20 movement, said bearing members and pinion be 25 ing slidable as a unit, and means for causing them to slide in the casing.

CHARLES A. MOORE. PRESTON WHITCOMB. 

